Many operating systems have the concept of an operator/administrator console. Operating systems with a text-based interface on personal computers and servers typically implement the text-based operator/administrator consoles via keyboard input and built-in video. The operator/administrator console facilities include support for what is known as “virtual consoles,” which can be switched via a hot-key and provide concurrent separate login sessions into the system. Additionally, the console may be switched into a “kernel console,” which allows interactive access to all kernel log messages or to be put into a special live debugging mode to dump kernel and system information. In some cases, the same console output can be used for a crash debugger and/or for panic screen interactions.
One problem is that some servers have no “built-in” console support because these servers lack a video card/controller. The only way to interface with the operating system (OS) on these “headless” systems is through the serial port. There is usually only one serial port on such headless systems. Although the OS supports operation via a single serial console, the experience is different from the traditional keyboard and video consoles. There is no support for virtual consoles, meaning that there can only be one logical login session running. Also, there is limited support for kernel interaction (e.g., there is no interactive kernel logging console, no interactive panic screen, and no live debugging support). Further, the user interface for headless systems is wholly different, with a mixture of boot options and tricks that administrators need to learn to only get a partial feature set as compared to the traditional keyboard and video consoles.